"The 'contact group' you're proposing is completely useless and unnecessary," Venezuelan Foreign Minister Delcy Rodriguez fumed at a meeting of the Organization of American States (OAS) in Cancun, Mexico.

"The only way you could impose it would be to send in your Marines — who would meet with a crushing response from Venezuela if they dared make such a misstep."

The outburst came as US Deputy Secretary of State John Sullivan tried to rally support for an OAS resolution to send regional mediators to Venezuela, where running street battles at anti-government protests have left 74 people dead since April.

Sullivan responded to Rodriguez — who called him "el jefe" (the boss) — with a three-word rebuttal: "Distractions, distortions and irrelevancies."

The tense exchange came a day after OAS foreign ministers — divided between allies and critics of Caracas — failed to agree on a joint response to the Venezuelan crisis.

The draft resolution backed by the United States fell three votes shy of the 23 it needed to be adopted by the 34-nation group.

A member of the riot security forces, right, points what appears to be a pistol toward a crowd of demonstrators during a rally against Venezuelan President Nicolas Maduro’s government in Caracas, June 19, 2017. Thomson Reuters

Sullivan is now pushing to take the matter up in the OAS General Assembly, which is also convening in Cancun this week, and where the vote threshold is lower: a simple majority of 18 votes.

But Venezuela has repeatedly said it will not respect decisions taken by the OAS, which it is in the process of quitting — a procedure that will take two years.

Rodriguez also lashed out at other countries that supported the US-backed proposal.

She referred to Peru as a "lapdog of imperialism" and called Costa Rica's foreign minister a "political illiterate who knows nothing about Venezuela."

Pummeled by the plunge in oil prices since mid-2014, Venezuela is in the grip of an economic and political crisis that is causing desperate shortages of food, medicine and other basic essentials.

Protesters want elections to remove President Nicolas Maduro from power.